1. Field of the Invention
The present invention relates to a heat sink, a cooling device for an electronic device and an electronic device.
2. Description of the Related Art
An electronic device such as a personal computer includes an electronic member such as an LSI, and the amount of heat produced by electronic members such as LSIs is increasing. On the other hand, the electronic device is required to become thinner and more compact. Therefore, an electronic device which is small in size and has a high cooling performance is required.
Various heat sinks are used to dissipate the heat produced by an electronic member such as an LSI. In addition, a cooling device including a fan and a heat sink can be used. For example, a heat sink has been proposed in which the surface of the base, which is the main body of the heat sink, is formed stepwise, with the surface being elevated higher toward the center (refer to Japanese Unexamined Patent Publication (Kokai) No. 11-40967, for example). Another heat sink has been proposed which has a plurality of fins provided in parallel to each other on the surface of a base, with the ends of the fins on the upstream side of the air flow being set back further toward the center (refer to Japanese Unexamined Patent Publication (Kokai) No. 10-209351, for example). A further heat sink has been proposed in which fins are provided on the top surface and the lower surface of a base (refer to Japanese Unexamined Patent Publication (Kokai) No. 2001-15969, for example). On the other hand, a cooling device has been proposed in which a fan is arranged above a heat sink (refer to Japanese Unexamined Patent Publication (Kokai) No. 2001-274575, for example). A further cooling device has been proposed in which a fan is arranged adjacent to a heat sink (refer to Japanese Unexamined Patent Publication (Kokai) No. 2002-64167, for example).
It is desirable to use a large heat sink (the base is wide, the base is thick, or the fins provided on the base are tall) in order to cool an LSI which produces a large amount of heat. However, the space for arranging a heat sink internally in an electronic device such as a notebook-type personal computer is very small. For example, in the case of a heat sink having fins, it is possible to increase the amount of heat to be dissipated by increasing the thickness of the base of the heat sink or the thickness of the fins, but the heat sink as a whole becomes taller. On the other hand, in the case of a cooling device in which a fan is provided above a heat sink, the cooling device as a whole becomes taller. If a configuration in which a fan is arranged adjacent to a heat sink (a fan and a heat sink are arranged side by side on the same plane) is adopted, the cooling device as a whole does not become very tall. In this case, it is preferable for the heat sink to be cooled efficiently by the air delivered by the fan.
The object of the present invention is to provide a small heat sink capable of cooling an electronic member efficiently, a cooling device for an electronic device and an electronic device.